const path = require('path');

const rootCompiler = compiler => {
  while (compiler.parentCompilation) {
    compiler = compiler.parentCompilation.compiler;
  }
  return compiler;
};

const compilerContext = exports.compilerContext = function compilerContext(compiler) {
  return rootCompiler(compiler.compiler ? compiler.compiler : compiler).context;
};

const relateNormalPath = exports.relateNormalPath = function relateNormalPath(compiler, key) {
  if (typeof key !== 'string') {return key;}
  if (compilerContext(compiler) === key) {
    return '.';
  }
  if (key === '') {
    return key;
  }
  return path.relative(compilerContext(compiler), key).replace(/\\/g, '/');
};

const relateNormalRequest = exports.relateNormalRequest = function relateNormalRequest(compiler, key) {
  return key
  .split('!')
  .map(subkey => relateNormalPath(compiler, subkey))
  .join('!');
};

const relateNormalModuleId = exports.relateNormalModuleId = function relateNormalModuleId(compiler, id) {
  return id.substring(0, 24) + relateNormalRequest(compiler, id.substring(24));
};

const relateNormalLoaders = exports.relateNormalLoaders = function relateNormalLoaders(compiler, loaders) {
  return loaders.map(loader => Object.assign({}, loader, {
    loader: relateNormalPath(compiler, loader.loader),
  }));
};

const relateNormalPathArray = exports.relateNormalPathArray = function relateNormalPathArray(compiler, paths) {
  return paths.map(subpath => relateNormalPath(compiler, subpath));
};

const relateNormalPathSet = exports.relateNormalPathSet = function relateNormalPathSet(compiler, paths) {
  return relateNormalPathArray(compiler, Array.from(paths));
};

/**
 *
 */

const contextNormalPath = exports.contextNormalPath = function contextNormalPath(compiler, key) {
  if (typeof key !== 'string') {return key;}
  if (key === '.') {
    return compilerContext(compiler);
  }
  if (key === '') {
    return '';
  }
  return path.resolve(compilerContext(compiler), key).replace(/\//g, path.sep);
};

const contextNormalRequest = exports.contextNormalRequest = function contextNormalRequest(compiler, key) {
  // return key
  // .split('!')
  // .map(subkey => contextNormalPath(compiler, subkey))
  // .join('!');

  let i = -1;
  let j = -1;
  let _newkey = '';
  while ((i = key.indexOf('!', i + 1)) !== -1) {
    _newkey += contextNormalPath(compiler, key.substring(j + 1, i));
    _newkey += '!';
    j = i;
  }
  _newkey += contextNormalPath(compiler, key.substring(j + 1));
  return _newkey;
};

const contextNormalModuleId = exports.contextNormalModuleId = function contextNormalModuleId(compiler, id) {
  return id.substring(0, 24) + contextNormalRequest(compiler, id.substring(24));
};

const contextNormalLoaders = exports.contextNormalLoaders = function contextNormalLoaders(compiler, loaders) {
  return loaders.map(loader => Object.assign({}, loader, {
    loader: contextNormalPath(compiler, loader.loader),
  }));
};

const contextNormalPathArray = exports.contextNormalPathArray = function contextNormalPathArray(compiler, paths) {
  return paths.map(subpath => contextNormalPath(compiler, subpath));
};

const contextNormalPathSet = exports.contextNormalPathSet = function contextNormalPathSet(compiler, paths) {
  return new Set(contextNormalPathArray(compiler, paths));
};

/**
 *
 */

const maybeAbsolutePath = exports.maybeAbsolutePath = function maybeAbsolutePath(path) {
  return /^([a-zA-Z]:\\\\|\/)/.test(path);
};

const relateAbsolutePath = exports.relateAbsolutePath = function relateAbsolutePath(context, absPath) {
  if (maybeAbsolutePath(absPath)) {
    return path.relative(context, absPath);
  }
  return absPath;
};

const relateAbsoluteRequest = exports.relateAbsoluteRequest = function relateAbsoluteRequest(context, absReq) {
  return absReq
  .split(/!/g)
  .map(path => relateAbsolutePath(context, path))
  .join('!');
};